The invention relates to a method for producing a corona ignition device.
Corona ignition devices comprise a housing tube in which a coil is arranged, said coil being connected to a center electrode. The center electrode is stuck in (plugs into) an insulator that is fastened by means of a mount to a front end of the housing tube. At its rear end, the housing tube carries a plug connector, via which the corona ignition device can be connected by means of a suitable mating plug connector to the on-board power supply system of a vehicle.
The center electrode, together with the insulator and the mount, provides a capacitance, which together with the coil forms an oscillating circuit. If the oscillating circuit is resonantly excited, this leads to a voltage step-up between the center electrode and the walls of the combustion chamber or the housing tube of the corona ignition device. This leads to the formation of a corona discharge in the combustion chamber. Fuel in the combustion chamber of an engine can thus be ignited by means of a corona discharge starting from the center electrode.
Compared to conventional spark plugs, which ignite fuel/air mixtures by means of arc discharges, corona ignition devices have the advantage of a much lower burn-up of the electrodes or ignition tips. Corona ignition devices therefore have the potential of a much longer service life compared to conventional spark plugs.
A common cause for premature failure of corona ignition devices are shunts and dielectric breakdowns in the interior of the housing tube. In order to prevent this, housing tubes of corona ignition devices are filled up with electrically insulating casting compound. Another possibility, which is described in EP 1 662 626 B1, consists of filling the housing tube with insulating gas.